This research is about concrete equivalent to blast furnace cement type A, which is manufactured by mixing ordinary Portland cement and blast furnace cement type B, which is an environmentally friendly concrete that can be widely used in the superstructures of buildings As a result, it was confirmed that although the compressive strength and carbonation resistance at a young age decreased, there were no major differences in other durability. Additionally, It was confirmed that variations in measurements during manufacturing have little effect on the fresh properties and strength properties.

In this study, we investigated the applicability of an abrasion acceleration machine to floors of actual buildings in order to establish method for predicting changes in floor slipperiness caused by abrasion resulting from walking. As it was found that the existing abrasion method were not appropriate for rubber tiles, a new abrasion method was investigated. As a result of various investigations, we were able to reproduce the abrasion situation of floors in actual buildings by using a new method in which a specific grain size and amount of silica sand was spread at a specific frequency while abrasion was being performed.

Abrasion induced by caster wheel traffic on concrete floors treated with surface reinforcing materials was investigated. The effects of concrete finishing, curing conditions, and the age of the surface reinforcing materials on abrasion resistance were evaluated.

The results demonstrate that proper curing after concrete placement is essential for enhancing the abrasion resistance of surface reinforcing materials against caster wheel traffic. Additionally, it was found that a specific curing period is required for the surface reinforcing materials to achieve their full abrasion-resistant capabilities.

Autoclaved lightweight aerated concrete is one of high insulation performance construction material because of its aerated structure. It will be needed to improve their insulation performance for energy-saving building to solve environmental issue, so we focused aerated process and had experimental study about foaming characteristics and then evaluated its effect to insulation performance. We grasped the tendency of foam size with aluminum powder and foam stabilizer and revealed that smaller foam size is better for thermal conductivity and compressive strength.

In recent years, the use of wood in medium-sized to large-sized non-residential buildings has been on the rise, and many examples with large-span roof structures with spans exceeding 10 m have been reported. The authors focused their attention on the Vierendeel roof structure, which is a type of truss structure. In this paper, the authors conducted loading tests and continuous loading tests to understand the basic mechanical properties and creep characteristics of a wooden Vierendiel frame and a wooden hybrid frame with cables added using full-scale test specimens.

The objective of this study is to propose abbreviated calculation methods on yield strength and initial stiffness for Multi-layered plywood (MLP) connection using drift pinned joint with steel inserted plate. Exact calculated values of yield strength and abbreviated calculated values of it were compared, and did the same with initial stiffness, and it was shown that there was little difference between them. Connection tests were conducted, and abbreviated yield strength was close to experimental values; therefore, its validity was confirmed. Regarding initial stiffness, abbreviated value was matched to some degree to experimental values; however, there is still room for improvement.

To verify strengths of steel bar-timber composite beam after the 60-minute burning test reported in a previous paper, a method is proposed to estimate temperature profile in uncharred area inside the beam using temperature-burning time curves within each specimen to be measured, and calculations for bending and shearing stress within the beams are conducted using by the existing reduction rate of elastic modulus and strength of timber as temperature increases. The relationship between stress profile in timber expected in the calculation of strength of the beam according to the proposed design method and those under the burning test is clarified.

The authors propose a new defined tensile stress distribution for steel fiber reinforced concrete (SFRC) to evaluate the flexural strength of SFRC beams. It is a simplified formula based on the SFRC tensile stress – tensile strain relationship curves. This study confirmed that the flexural strength of SFRC beams is influenced by the orientation factor of steel fibers which is in turn affected by the fiber amount. The authors also propose a formula for this orientation factor expressed by the fiber volume ratio. Using these proposed formulae, the flexural strength (allowable, yielding, ultimate levels) of SFRC beams could be accurately evaluated.

Targeting reinforced concrete buildings in which beams yield first, a design method for RC beams was proposed that uses high-strength rebars at the top of the beams and provides secondary stiffness in the skeleton curve to reduce residual deformation after an earthquake. The proposed beam controls the hysteresis characteristics by the yield strength of the upper reinforcement. Using analytical models of columns and beams created based on the results of loading experiments, several types of analytical models of RC frames were created, and response analyses were performed on each model using earthquake waves to clarify their structural performance.

After a major earthquake, quick inspections are conducted to confirm buildings’ safety immediately, but these inspections require experts in architectural engineering. In this study, earthquake response analyses are conducted on six-story and three-story steel-framed hospital buildings under 115 sets of earthquake ground motions of seismic intensity 6 or larger in the Japan Meteorological Agency scale to evaluate the maximum inter-story drift angle, residual deformation angle and damage degree of beam end, and a basic investigation of the emergency risk evaluation criteria is conducted based on the relation among these responses. The residual deformation angles judging the damage states are proposed.

Fillet welds are widely used in steel frame construction. However, the ultimate strength when the load acts obliquely to the weld line has not been theoretically clarified. In this paper, the strength of inclined fillet welds is derived based on the upper bound theorem of limit analysis and compared with experimental results and finite element numerical analysis results. As a result, a strength evaluation method is presented that includes the effects of the strength ratio of the weld metal to the base metal and the penetration amount.

Evaluating the risk of a large portfolio consisting of a vast number of buildings and structures is computationally intensive, and when considering the correlation between locations based on distances using Monte Carlo simulations, the computational burden becomes extremely large. This study focused on portfolio reduction and proposed a reduction method using the k-means method, as well as a method for determining characteristics after reduction. The proposed method was applied to a portfolio of 346 buildings located in the Kanto region, and its advantages were confirmed. Insights regarding portfolio reduction were also organized through sensitivity analysis.

We estimated seasonality for the number of people requiring hypothermia treatment due to building damage for Sapporo, Hokkaido using Duration Limited Exposure (DLE). The target victims were defined as trapped people by the collapsed buildings. Estimates indicate, in February, about 60% of the trapped victims 6 hours after and all of them developed hypothermia 12 hours after the disaster. Furthermore, DLE was about 4 hours shorter in severe winter than in early spring. As a damage reduction measure, the number of hypothermia was reduced by 54% if all buildings were earthquake-proofed to a seismic rating of over 1.0.